is destined to be one of the wonders of the world, as it will contain the greatest concrete span yet constructed. The main span will be 233 feet long and 120 feet high by sixty feet in width. With four other spans the total length will be 520 feet, crossing a ravine through which runs the Wissahickon creek, and connecting two populous sections of the city, Germantown and Roxborough. At Plauen, Saxony, there is a masonry bridge with an arch 295 feet long, and over the Petrusse river, in Luxemburg, there is another with a span of 275 feet. The famous Cabin John bridge, at Washington, D. C., has a span of but 219 feet.

The abutments, foundations and approaches of the bridge, as well as the false work, were placed in position last fall. The bridge proper is of plain concrete, although re-enforced concrete will be used in certain parts of the structure. The plans for the bridge were drawn by the city's Bureau of Surveys, and the work is being done by the city's employes. The total cost of the structure is estimated at $256,000, and it is believed that it will be completed in about one year.

nearly three days, all would have been saved; as fifteen seconds after firing the shot people can be conveyed from the wreck to the shore.

Albert Meyer invented this projectile and designed the cannon a week after the Valencia disaster, as he saw the necessity of having a device which was not dependent on human aid from shore.

Great Concrete Span AFTER long delays occasioned by in

clement weather, work is being pushed at Philadelphia on a bridge which

steam heated. These cars will otherwise be equipped with everything conducive to comfort and safety, being provided with feed and water compartments, harness lockers, and suitable berths for the men in charge of the horses.

Just as only the wealthy can afford special and private cars, just so will the new cars be used exclusively for the transportation of valuable horses principally owned by the millionaires of Chicago and New York, who not infrequently ship their horses to California for the winter, returning them in the spring. They do not object to paying the extra rates for the special cars for their horses; in fact, had rather pay it than have them shipped in the ordinary stock cars. The railroad officials are of the opinion that palace cars for horses will be economy on the part of the roads in the long run, as they are often called upon to pay heavy damages when horses have been shipped in cars which were not what they should have been.

In the meantime the ordinary animal

will continue to travel in the old-fashioned, ill-ventilated stock cars just as the common people will continue to travel in the ordinary day coaches.

Handles Engines Like Toys

THE illustration shows a mammoth traveling crane in use at the Collinwood, Ohio, railroad shops. The capacity of this crane is one hundred and twenty tons, and in all probability this capacity will be greatly increased. The photograph shows the huge locomotive hung up like a mere toy. For quickly conveying an engine from one part of a crowded shop to another, or for removing it entirely from the building, such a crane is invaluable.

Remarkable improvements have been made, in recent years, in the mechanical handling of pieces of machinery, etc. The traveling crane is one of the most efficient aids to industrial progress.

Reason Enough

"JACKIE," said the boy's mother, your face is fairly clean, but how did you get such dirty hands?"

"Washin' me face," said the boy.-Exchange.

The Wrong Kind of Glass

He was a young and smart-looking Scotch clergyman, and was to preach a "trial" sermon in a strange church. Fearing that his hair might be disarranged or that he might have a smudge on his face, he quietly and significantly said to the beadle, there being no mirror in the vestry, "John, could you get me a glass?" John disappeared, and after a few minutes returned with something under his coat, which, to the astonishment of the divine, he produced in the form of a bottle with a gill of whisky in it, saying, "Ye mauna let on aboot it, meenister, for I got it as a special favor; and I wadna hae got it ava if I hadna told them it was for you."-Tattler.

ARCHIMEDES,' reads the pupil, "leaped from his bath shouting, "Eureka! Eureka!" "One moment, James," says the teacher. "What is the meaning of 'eureka'?" "Eureka' means 'I have found it.'"

ki

"Very well. What had Archimedes found?" James hesitates for a moment, then ventures hopefully, "The soap, ma'am."-Judge.

Could Go-Ahem!

A MAID, when her young mistress was on the high road to recovery, announced in a loud voice: "The board of Hell is down stairs."

"You tell them to go where they came from," replied the nurse, who was annoyed at being interrupted in the discharge of her duties.

The Board of Health could not feel complimented by its new designation, though often its inspectors are accused of playing the deuce in the home where there has been a contagious disease.

Another Fake Exposed UNCLE JOSH, fresh from Upcreek, had been inspecting the family ice-box. "Henry," he said, "you told me you was gittin' artificial ice. The feller that sells it to you is foolin' you. I've looked at it, and tetched it, and if it ain't real ice, by gum, I never saw any."Chicago Tribune.

"Yes."

"Well, the pretty one I would call a vision, but the other one-she's a sight."-Cleveland Plain Dealer.

Setting Her Right

SHOPPER: Where is the corset department? FLOORWALKER: Straight back. "No, straight front."-Life.

Another Unfortunate

SHE "He married her for her money. Wasn't that awful?"

HE "Did he get it?" SHE "No."

HE "It was."-Judge.

The Greater Power

HEALER "The first thing you must do is to banish all fear from your mind. You mustn't even fear God."

PROSPECTIVE PATIENT-"But, my dear sir, it isn't a question of God, it's a question of my wife."-Life.

Absolutely Essential

WILLIAM O'BRIEN in his "Recollections," tells this story of Dr. Coke, the great archbishop of Cashel: "Once on one of his examinations of the children for confirmation the archbishop put to a little girl the question from the catechism: 'What is the preparation for matrimony?' The little one blushed and giggled and put the corner of her bib in her mouth by way of answer. The question was

Electrolytic Rectifier

I am about to install a rectifier for a single phase current, and have been advised to use an electrolytic rectifier. Will you please give me information regarding its construction and theory?-J. T.

One very successful form of rectifier used in England is that known as Nodon's "Electric Valve." As will be noted from the sketch, an iron cylinder is used as one electrode, the cylinder containing a solution of ammonium phosphate. A rod consisting of an alloy of aluminum. and zinc passing through a plug of insulating material in the bottom of the cylinder, forms the other electrode. Current passes freely from the iron to aluminum, but if an attempt is made to send a current in the opposite direction a non

ELECTRICAL RECTIFIER.

conducting film immediately forms on the surface of the aluminum and the current is practically arrested. When the cell is connected across alternating current mains an undirectional or rectified current will be obtained. From experimental work it has been determined that this type of cell will operate at an efficiency of 70 per cent. There are cells in the market which operate on the above principle, but their construction is not exactly the same.

Drawing to Scale

What is the meaning of "drawing to scale?" -L. R. A.

The meaning of drawing to scale is that the drawing when done bears a definite proportion to the full size of the particular part, or, in other words, is precisely the same as it would appear if viewed through a diminishing glass.

When it is required to make a drawing to a reduced scale, that is, of a smaller size than the actual size of the subject, say, for instance, one-half full size, every dimension of the subject in the drawing must be one-half the actual size; in this instance, one inch on the object would be represented by one-half inch. Such a reduced drawing could be made with an ordinary rule; this, however, would require every size of the object to be divided by the proportion of the scale. which would entail a very great loss of time in calculations. This can be avoided by simply dividing the rule itself by two, from the beginning. Such a rule, or scale, as it is generally called, will be divided into one-half inches, each half inch representing one full inch divided into one-half, one-quarter, one-eighth,